The invention relates to a balance, in particular a precision balance or an analytical balance with a weighing pan enclosed in a weighing compartment, wherein the weighing compartment is delimited by a draft shield in which at least two walls are slidable to open and close the weighing compartment, and wherein the slidable walls are coupled to each other to allow a simultaneous opening and closing of both walls.
Balances of this type belong to the familiar state of the art and are used primarily in laboratories, e.g., for dispensing substances by weight when performing chemical analyses.
The European patent application EP 0 234 008 A2 discloses a balance of this type, wherein the draft shield has a fixed glass window at the front, rearwards-slidable doors at the sides, and a rearwards-slidable cover panel on top. The two lateral sliding doors can be connected to each other by way of a plate that is slidably arranged underneath the balance. Latches that are preferably configured as bolts engaging a recess by sliding back and forth are integrated in the door handles and allow the sliding doors and the cover panel to be coupled to each other as needed. By means of the plate connecting the door handles that are fastened at the bottom of each of the two sliding doors, it is possible to move both doors simultaneously as well as move either one of the doors by pushing the handle on the opposite side.
The concept of moving sliding windows together as well as opening and closing a lateral sliding window through actuation from the opposite side is also shown for the balance disclosed in EP 0 547 298 A1, where each of the two lateral sliding windows preferably consists of two panels set at an obtuse angle to each other, which requires that the windows slide in curved guide tracks. The mechanism which is arranged at the underside of the balance for moving the two lateral sliding windows therefore has two flat actuation levers protruding on both sides of the housing, which are pivoted on the floor of the housing so that they can be swiveled back and forth, and which are connected by a flat coupling element in the form of a slidable plate that is likewise arranged on the floor of the housing. The lateral sliding windows are in this case coupled to the slidable plate either through a vertically movable bolt or through a small latch arranged in the lower part of the two-part handle and engaging a recess in the upper part of the handle.
In both types of balances of the foregoing description, the connecting- or coupling element, in particular the bolt or latch, is substantially hidden inside the handle. A person standing several meters away from the balance, e.g., when entering the laboratory, will therefore not be able to tell which of the different operating positions the balance is currently set for with regard to the coupling of the sliding windows to each other and/or to the sliding mechanism or the connecting plate.